In a 2015 sketch aired on Comedy Central’s “Inside Amy Schumer,” the one called “New Body,” Schumer played a woman shopping for a wardrobe for the body she’s always wanted. The clothing store clerk, thin and deadpan, is the perfect foil for Schumer’s chipper, play-along reactions. With those two perfect minutes you don’t realize the first time through how much Schumer and her writers are actually saying about the culture’s omnipresent assault on female self-image.

Take that sketch, add 105 minutes, and alter the tone from sly satire to droopy romantic seriocomedy, and you’ve got “I Feel Pretty.”

The comedian and actress has long been spot-on and ruthlessly funny about body issues and self-esteem. Ever since she got famous Schumer has weathered ridiculous tons of troll-based abuse online for not looking like a heroin-chic supermodel.

“Anyone who has ever been bullied or felt bad about yourself I am out there fighting for you, for us,” Schumer posted on Instagram two years ago, after the announcement that the “Trainwreck” star was earmarked for a live-action “Barbie” movie. (She’s since dropped out of that project, citing scheduling conflicts.)

“I Feel Pretty” arrives in the spirit of that Instagram post, though it’s a weirdly scrambled, two-faced sort of empowerment movie. Schumer plays Renee Bennett, who works in a ratty Manhattan Chinatown satellite office of a fashionable cosmetics firm. She has friends (played by Aidy Bryant of “Saturday Night Live” and Busy Philipps of “Vice Principals”) and plenty of smarts, but zero confidence and a barren dating life.

Watching “Big” on TV one night, she gets to thinking about wish fulfillment. She tosses a coin in a fountain, hoping she’ll suddenly become conventionally ha-cha and free-drinks gorgeous. And then it happens: After conking her head in spin class, in a harsh slapstick sequence, Renee wakes up delusional and seeing an entirely new woman in the mirror. Before the inevitable, wince-worthy moment of reckoning, “I Feel Pretty” follows Renee 2.0 as she revels in her newfound swagger, acing a job promotion and finding a nice, presentable, affable man (Rory Scovel, “The House”) while being tempted by a hunky Lothario (Tom Hooper, “Game of Thrones”).

The film takes a cue from “Working Girl,” “The Devil Wears Prada” and other Manhattan-set corporate fables. “I Feel Pretty” ushers its lowly heroine into a world of privilege, where insecurities run rampant, albeit more petitely. Valiantly, Michelle Williams takes the role of cosmetics firm CEO Avery LeClair, a supremely put-together woman who looks like Gwyneth Paltrow but sounds like a sedated version of Lina Lamont from “Singin’ in the Rain.” Her voice is her Achilles heel; what this woman needs is Renee 2.0 in her life, for moral support, a few ideas and some overdue sisterhood.

There’s a movie in that, and in all of the themes, really. The problem with this movie is one of strategy. Despite plentiful scenes affording Schumer room to show both sides of Renee, the sad sack and the strutter, veteran screenwriters and first-time feature film directors Abby Kohn and Marc Silverstein can’t settle on a tone, or allow Renee to breathe. Beauty, like confidence, is in the eye off the beholder: The idea is evergreen. And the filmmakers aren’t so crass as to go the “Shallow Hal” route, and turn the story into a skeezy, pathetic occasion for prosthetics and sniggering.

But “I Feel Pretty” keeps knocking its main character around and down, perpetually cutting to supporting characters’ reaction shots indicating their shock and disdain at this woman’s can-do air. The movie’s frankly depressing. That word, “depressing,” was in fact the first word I heard from all three college students, with whom I attended a screening.

This was hardly the case with “Trainwreck,” Schumer’s often riotous breakout movie vehicle, though her follow-up, “Snatched” (costarring Goldie Hawn), succumbed to all the wrong Hollywood contrivances. “I Feel Pretty” feels a lot closer to the latter. It’s just not funny or fresh enough, and that has everything to do with the material and how it’s handled visually, and nothing to do with the people on the screen.

Postscript: The degree to which Target is name-checked throughout “I Feel Pretty” takes things beyond product placement into product assault.